Utensils exist, either being proprietary products or adaptions of well known cooking devices, for steam cooking of food or otherwise cooking of food in a closed container.
Steam cooking devices usually comprise a perforated food container placed on or within a receptacle containing water and designed so that when said water is heated the steam produced passes around and/or through the food to cook it. This method of cooking suffers from the fact that much of the flavour and food value is extracted by the steam and lost in the re-condensed water.
Other closed containers such as casseroles, either heated in an oven or over an open heating appliance or incorporating direct electric heating elements, tend to retain some moisture and flavour but being subject to direct heat have the disadvantage of possible local overheating or even burning of the food and loss of both moisture and food value by boiling over or by evaporation.
The devices known as "slow cookers" are an attempt to alleviate the burning problem inherent in casseroles by surrounding a cooking pot with an insulated jacket containing a very low powered electrical heating element, usually of the order of about 100-130 watts, or the same as an electric light bulb. Whilst such devices do retain moisture and flavour within the food, the very low heating power inevitably resuls in a long delay before the food reaches cooking temperature. During this long heat up period there is a high possibility of rapid reproduction of micro-organisms within the food, which in turn produce toxic by-products during their life and reproduction cycles. On reaching higher temperatures the micro-organisms are destroyed, but the toxic by-products can remain in the food, often giving rise to a characteristic `taint` and pass into the digestive system of the consumer. This can be potentially hazardous to health, particularly in countries with low standards of food hygiene resulting in high levels of incipient bacteria in raw foods.
In the traditional method of cooking known as "Bain-Marie", the food is protected from direct heat by placing the food container in a shallow pan containing water which is then heated. This method is normally used only for low temperature cooking of delicate foods otherwise subject to being spoilt by overheating.
The invention has among its objects to provide a cooking vessel in which food can be cooked with an initial relatively rapid increase in temperature, without risk of burning and without undue loss of flavour of the food during cooking or spoiling of the food by drying.
It is also among the objects of the invention to provide a cooking vessel in which different foods can be cooked simultaneously with significant intermixing of the flavours of the different foods.
With these objects in mind and in accordance with the invention, a cooking vessel for oven cooking comprises an outer vessel to contain a quantity of water, an inner vessel to contain food, and a lid to close the outer vessel with the inner and the outer vessel and the lid relatively so shaped and located one with another as to form therebetween a space, and with the inner vessel and the lid relatively so shaped and disposed as to form a further space therebetween above food contained in the inner vessel, in which space, when the vessel is heated, a controlled release, circulation and recondensation of water vapour from the water contained in the outer vessel can occur, and in which further space, when the vessel is heated, a controlled release, circulation and re-condensation of further water vapour from the food contained in the inner vessel can occur, without undue mixing of the water vapour and further water vapour and without undue loss of the water vapour from the cooking vessel.
A cooking vessel according to the invention can protect the food from overheating during cooking whilst retaining moisture, flavour and food value, but also allowing for slow or rapid cooking as preferred. Special recipes have been prepared to take advantage of the improved yet simplified method of food preparation thus offered. Ancilliary components can be added to the vessel to make the fullest use of its unique cooking advantages.